The present invention relates to a semiconductor wafer support carrier used for supporting semiconductor wafers during liquid phase processes.
In semiconductor device manufacturing processes, semiconductor wafers undergo a variety of liquid phase processes. For example, semiconductor wafers undergo a washing process, which removes impurities from the surfaces of the semiconductor wafers. They then undergo an LPD process, which forms an SiO.sub.2 film on the surfaces of the semiconductor wafers by a precipitation reaction in a supersaturated solution.
In these liquid phase processes, the semiconductor wafers are supported by the semiconductor wafer support carrier. The semiconductor wafer support carrier supporting the semiconductor wafers is placed in and out of the process liquid.
However, when the semiconductor wafer support carrier is withdrawn from the process liquid, it often happens that dust particles and the like in the process liquid adhere to the surfaces of the semiconductor wafers. In this case, minute pattern forming processes and the like thereafter are affected by this adhering dust.
FIGS. 9 and 10 show a conventional semiconductor wafer support carrier.
In FIGS. 9 and 10, a liquid phase process apparatus 1 is provided with a vessel 2 filled with process liquid 3. A conventional semiconductor wafer support carrier 5 is provided with a lower support stand 6 supporting the lower ends of semiconductor wafers 4. The semiconductor wafers 4 supported by the semiconductor wafer support carrier 5 are dipped in the process liquid 3 within the liquid phase process apparatus 1, during the liquid phase process. After that, the semiconductor wafers 4 are, with the semiconductor wafer support carrier 5, drawn out of the process liquid 3.
In general, the semiconductor wafer support carrier 5 supports a plurality of semiconductor wafers 4, for example, twenty five semiconductor wafers, depending on the manner in which the semiconductor wafers are spaced. Many dust particles 7 float on the surface of the process liquid 3.
When the semiconductor wafers 4 are drawn up out of the process liquid 3 by the semiconductor wafer support carrier 5 after the liquid phase process, the dust particles 7 on the surface of the process liquid 3 adhere to the surface of the semiconductor wafers 4.
For example, in semiconductor wafer washing process in which it is relatively easy to secure the cleanliness of the process liquid 3, the amount of dust particles adhering to the surfaces of the semiconductor wafer and having diameters of over 0.3 .mu.m is in the order of several tens to several hundreds of particles per semiconductor wafer having a diameter of 5 inches (see FIG. 7).
On the other hand, in a resist exfoliation process or an LPD process, in which it is easy for dust particles to form, the amount of dust particles per semiconductor wafer is about 100.about. about 1000 particles.
The dust particles adhering to the surface of the semiconductor wafer 4 cause a great deal of trouble in the minute pattern forming processes of the semiconductor wafers thereafter.
These phenomena are shown in FIG. 11.about.13.
FIG. 11 shows the sectional side view of the semiconductor wafer. In FIG. 11, a numeral reference 8 is a substrate of the semiconductor wafer. Dust particles 7 adhere to the surface of the substrate 8 during the liquid phase process of the semiconductor wafer. After that, a wiring material 9m is laminated on the surface of the substrate 8.
Next, certain shapes of wiring portions 9 are formed on the substrate 8 by etching the wiring material 9m of FIG. 11 (see FIGS. 12 and 13). FIGS. 12 and 13 show the top views of the semiconductor wafer.
However, it happens that the wiring portions 9 are separated by the dust particles 7, as shown in FIG. 12, when the wiring material 9m of FIG. 11 is etched. In this case, the wiring portions 9a and 9b, which should be properly connected, are separated by the dust particles 7, so that the wiring pattern formation of the semiconductor wafer becomes worse.
It also happens that the etching rest portion 9c remains under the dust particle 7 as shown in FIG. 13, when the dust particle 7 is positioned between the wiring portions 9 and the wiring material 9m of FIG. 11 is etched. In this case, the wiring portions 9d and 9e which should not normally be connected, are connected to each other through the etching resist portion 9c, so that the wiring pattern formation of the semiconductor wafer deteriorates further.
The method where the amount of the dust particles floating on the surface of the process liquid is reduced, has been employed in order to prevent the dust particles from adhering to the surfaces of semiconductor wafers.
That is, the method where the dust particles 7 are discharged with the process liquid 3 overflowing by supplying the process liquid 3 to the bottom portion of the vessel 2 has been employed.
The amount of dust particles 7 of the process liquid is decreased to some degree by the method as mentioned above, but the result of the method is not so apparent. This is because the dust particles 7 under the surface of the process liquid are discharged, but almost all the dust particles on the surface of the process liquid remain as shown in FIG. 14.
Thus, it is difficult to reduce the amount of dust particles in the process liquid 3. In the conventional liquid process, when the semiconductor wafer support carrier is drawn up out of the process liquid, the dust particles 7 of the process liquid 3 adhere to the surfaces of the semiconductor wafers 4, so that the minute pattern forming processes thereafter are affected by the adhering dust particles.
On the other hand, when the semiconductor wafer support carrier 5 supporting, for example, twenty five semiconductor wafers in a manner where the semiconductor wafers are standing and spaced in the longitudinal direction, is drawn up after the liquid phase process, many dust particles 7 adhere to the surfaces of the first semiconductor wafer (see FIGS. 7 and 8). However, the amount of the dust particles 7 adhering to the surfaces of the semiconductor wafers after the first (for example, the second, the third .... semiconductor wafers) is not as great.
This seems to be because dust particles floating before the first semiconductor wafer are easily drawn to the surfaces of the first semiconductor wafer, and because dust particles floating before the second or the third ... semiconductor wafers are prevented from approaching the surfaces of the corresponding semiconductor wafers by the front semiconductor wafers.